Airway balloon dilator

ABSTRACT

A medical apparatus for widening a stenosis in the airway of a patient which includes a central hollow core, an inflatable outer balloon, and at least one inner balloon inside the outer balloon. The apparatus also can include a flexible support member mounted on the external surface of the outer balloon with at least one microsurgical blade. The outer balloon can be dumbbell-shaped to keep the balloon in position over the stenosis when the balloon is inflated. The hollow core allows the patient to be ventilated during the procedure, the inner balloon(s) allow higher dilation pressures to be generated from inside the outer balloon, and the blade can form an effective cutting edge upon inflation of the outer balloon.

FIELD OF THE INVENTION

The present invention relates to medical care for the larynx, trachea orbronchi to relieve a stenosis. In particular, the invention relates to adevice for performing dilation of the larynx, trachea or bronchi.

BACKGROUND OF THE INVENTION

Management of stenosis of the trachea and bronchi, includinglaryngotracheal and subglottic stenosis, is one of the most challengingproblems for the head and neck surgeon. Subglottic stenosis is acongenital or acquired narrowing of the subglottic airway. In the earlytwentieth century subglottic stenosis was rare, and most cases occurredin adults. In the 1960's the incidence of acquired subglottic stenosisbegan to dramatically increase in the neonatal population, most likelythe result of increased survival of low-birth-weight infants and theincreased use of intubation in this population. In addition, long termintubation has become an accepted alternative to tracheotomy, leading tomore and more incidences of tracheal stenosis. Accordingly, themanagement of this condition has undergone a revolution, andreconstructive surgery efforts have been directed towards thispopulation.

Most patients with stenosis of the airway are referred to and aretreated at large academic centers by physicians specialty trained inthis area. There is a wide range of presentation of subglottic stenosiswith similarities and differences in the pediatric age group compared toadults. If the stenosis is severe and congenital, the patient will showsigns of airway distress at birth. More commonly, the pediatric patientwith subglottic stenosis is a neonate in the intensive care unit who hasfailed extubation, usually multiple times. Occasionally patients willpresent in clinic with a tracheotomy and the report of some airwayobstruction. Infants with mild subglottic stenosis may present withrecurrent croup-like illnesses and poor feeding. Adults usually have ahistory of prior intubation with symptoms of progressive shortness ofbreath and noisy breathing.

Airway balloon dilation has been shown to be a safe and effectivepalliative procedure for treatment of mild congenital and acquiredstenosis of the trachea and bronchi. Dilation of luminal human anatomyto treat stenoses can be dated back to the 16^(th) Century withesophageal “bougie” dilation. Specific medical applications of luminalballoon dilation range from alimentary canal and airway dilation todilation of the vasculature. Airway dilation dates back over 100 yearsago with the invention and subsequent use of the first beveled rigidbronchoscopes for stricture management. The use of balloons to dilateairway strictures emerged in the mid-1980's with reports describing morespecific utility of this procedure exclusively and in combination withother treatment modalities for airway stenosis. It was not until theearly 1990's that the first balloon dilation involving flexiblebronchoscopy was described.

Airway balloon dilation can be used to quickly re-establish tracheal orbronchial luminal patency to restore airflow in a way that doesn't causeexcessive trauma to the patient. According to Poiseuille's Law, anincrease in a tube's radius (such as the trachea or bronchus) canincrease airflow by a power of 4 (airflow =radius of the tube⁴). Thatis, very small increases in the luminal diameter of the airway can leadto large increases in airflow through the lungs. Literature has reportedthe use of balloon dilation for the treatment of benign strictures ofthe airway. Fibrotic strictures, such as those secondary totuberculosis, long-term endotracheal or tracheostomy tube placement,berylliosis, Wegener's granulomatosis, or sarcoidosis have been shown tobe treatable with airway balloon dilation therapy with general success.Additionally, balloon dilation has been useful in treating stricturessecondary to major surgical interventions such as lung transplantation,sleeve resection, bronchial re-implantation, and lobectomy. For thepurpose of treating strictures secondary to malignant obstruction,dilation therapy can be used alone or in combination with othertechniques such as surgical resection, cryotherapy, laser therapy, andstent placement, depending on the desired outcome for the patient.

Treatment with airway dilation can involve the clinician insertingincreasingly larger tubes into the airway (e.g. endotracheal tubes orcat-tail (bougie) dilators), which creates significant shear forces onthe airway mucosa. Although safe when performed by a skilled clinician,such a procedure sometimes induces unwanted trauma to the airway in theform of deep lacerations and hemoptysis. Further, current dilationpractices do not permit dilation of a tracheal stenosis that is distalto a narrowing of the proximal airway (i.e. a mild subglottic stenosis).

Current airway balloon dilation procedures are typically carried outusing angioplasty balloons; however, several limitations to the use ofangioplasty balloons become evident when used on the airway. Forexample, it may be difficult to adequately ventilate the patient duringthe dilation period, since the typical angioplasty balloon does notinclude a connection to an oxygen source. Further, the shape of theangioplasty balloon may predispose the balloon to slide out of placeduring dilation, or the balloon may be limited to the amount of pressurethat can be applied before the balloon bursts. Also, the typicalangioplasty balloon can usually stretch the airway lumen but notpermanently dilate it. Other factors associated with failure of airwayballoon dilation include previous attempts at endoscopic repair,circumferential scarring, and loss of cartilaginous support.

In light of the foregoing, it would be advantageous to provide a balloondilator for the airway of a patient that is able to allow ventilation ofthe patient during balloon inflation. It would also be helpful toprovide an airway balloon dilator that can provide increased inflationpressures during balloon dilation of the airway without balloon rupture.Further, it would be beneficial to provide a balloon that will not slipout of place in the patient's airway during balloon inflation. Finally,it is desirable to provide an airway balloon dilator that is capable ofcontrolled cutting of scar tissue.

SUMMARY OF THE INVENTION

The present invention provides an airway balloon dilator for use toquickly re-establish laryngeal, tracheal or bronchial luminal patency torestore airflow in a way that avoids excessive trauma to the patient.

One aspect of the invention provides an apparatus for performing anairway balloon dilation procedure at the site of a stenosis in theairway of a patient, the apparatus comprising a central axis, a hollowcore adapted to allow the patient to be ventilated therethrough, aninflatable outer balloon having an external surface, and at least oneinflatable inner balloon, the apparatus being insertable into the airwayof a patient for movement of the balloons therein between a deflatedconfiguration and an inflated configuration, the at least one innerballoon configured to inflate inside the outer balloon yet separatelyfrom the outer balloon.

Another aspect of the invention provides a method for performing anairway balloon dilation procedure at the site of a stenosis in theairway of a patient, the method comprising: (1) inserting an apparatusinto the airway, the apparatus including a central axis, a hollow coreadapted to allow the patient to be ventilated therethrough, aninflatable outer balloon having an external surface, and at least oneinflatable inner balloon, the apparatus being insertable into the airwayof a patient for movement of the balloons therein between a deflatedconfiguration and an inflated configuration, the at least one innerballoon configured to inflate inside the outer balloon yet separatelyfrom the outer balloon; (2) advancing the apparatus within the airwayuntil the outer balloon is across the stenosis; and (3) inflating theballoon to cause and allow the external surface of the balloon to expandupon and dilate the stenosis.

Another aspect of the invention provides an apparatus for performing anairway balloon dilation procedure at the site of a stenosis in theairway of a patient, the apparatus comprising a central axis, a hollowcore adapted to allow the patient to be ventilated therethrough, aninflatable, dumbbell-shaped outer balloon having an external surface, atleast one inflatable inner balloon, a flexible support member mountedalong the central axis of the apparatus and on the external surface ofthe outer balloon, the flexible support member being substantiallycompliant with the external surface of the outer balloon during movementtherewith, and at least one microsurgical blade attached to the supportmember and adapted to form an effective cutting edge upon inflation ofthe outer balloon, the apparatus being insertable into the airway of apatient for movement of the balloons therein between a deflatedconfiguration and an inflated configuration, the at least one innerballoon configured to inflate inside the outer balloon yet separatelyfrom the outer balloon, the dumbbell shape of the outer balloon adaptedto hold the outer balloon in position over the stenosis, and the atleast one blade adapted to form an effective cutting edge upon inflationof the outer balloon.

The nature and advantages of the present invention will be more fullyappreciated from the following drawings, detailed description andclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate embodiments of the invention and,together with a general description of the invention given above, andthe detailed description given below, serve to explain the principles ofthe invention.

FIG. 1 is a perspective view of one embodiment of the balloon dilator ofthe present invention.

FIG. 2 is a perspective view of one embodiment of the balloon dilator inwhich the outer balloon has a dumbbell shape and multiple innerballoons.

FIG. 3 is a perspective view of a flexible support member havingmicrosurgical blades, the support member adapted to fit over the outerballoon according to one aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

As illustrated in FIG. 1, one embodiment of the present invention is anapparatus 10 for performing an airway balloon dilation procedure at thesite of a stenosis in the airway of a patient, the apparatus comprisingan inflatable outer balloon 12 which has an external surface 14. Theapparatus also comprises a central axis 16, a hollow core 18, and atleast one inflatable inner balloon 20 adapted to inflate inside theouter balloon. The apparatus 10 is typically insertable into the airwayof a patient for movement of the balloons 12, 20 between a deflatedconfiguration and an inflated configuration. Further, the inner balloon20 is designed to inflate inside the outer balloon 12 yet separatelyfrom the outer balloon, adding the ability of the apparatus to producehigh dilation pressures without balloon rupture.

As shown in FIG. 1, the hollow core 18 traverses the entire apparatus10. Typically the hollow core connects via a proximal ISO connector toan oxygen source such as an anesthesia circuit or the like, and isdesigned to allow the patient to be ventilated upon inflation of theballoons during the procedure, when the airway is otherwise occluded.The hollow core 18 is typically in the form of a central ventilatingtube which is necessarily strong to prevent the pressure of the balloonsfrom crushing the ventilating tube. The structure of the hollow core 18is typically similar to a small endotracheal tube with a dilating cuff,and the tube may be reinforced, e.g. with wire, in the area of the cuff.

As illustrated in FIG. 2, one embodiment of the invention is a balloondilator apparatus 30 in which the inflatable outer balloon 32 isdumbbell-shaped. This dumbbell shape typically has a variable thicknessat the proximal 34 and distal 36 ends of the balloon which allows theouter balloon 32 to stay in position over the stenosis during inflation.In the embodiment of FIG. 2, the apparatus 30 can include a plurality ofinner balloons 40, 42, 44, wherein inner balloon 44 is contained insideinner balloon 42, which is contained inside inner balloon 40. All of theinner balloons 40, 42, 44 are contained inside outer balloon 32, and aretypically separately inflatable. Such an embodiment could be used withlarger diameter outer balloons, e.g. between about 10 to about 20 mm. Inthis embodiment, the inner balloons 40, 42, 44 can be either dumbbellshaped or a “double cone” shape as seen with most angioplasty typeballoons, and are inflated sequentially if higher pressures cannot beachieved by the outer balloon. Having a balloon dilator thatincorporates multiple interconnected smaller balloons can achieve thedesired pressure without risking balloon rupture during inflation.

During inflation, the proximal 34 and distal 36 ends of the outerballoon 32 inflate first, forming the “dumbbell” shape, thereby trappingthe stenotic airway segment at the central portion 38 of the balloon 32,so that the outer balloon 32 does not slip out of position. Then, as thepressure in the balloon is increased, the central portion 38 of theballoon fully inflates at the site of the stenosis.

As illustrated in FIG. 3, one embodiment of the invention can include aflexible support member 50 that can fit over the apparatus, specificallyfitting over the outer balloon. The flexible support member 50 istypically made of a polyurethane material and includes a central axis 56mounted along the central axis of the apparatus. The support member isadapted to fit over the external surface of the outer balloon, and istypically substantially compliant therewith during inflation anddeflation. Support member 50 also includes at least one microsurgicalblade, and in FIG. 3 two surgical blades 52 are attached. Blades 52 forman effective cutting edge upon inflation of the outer balloon. Blades 52are typically made of stainless steel, and are elongated and permanentlymounted on the flexible support member 50. In use, when the supportmember 50 is placed over the outer balloon, the blade axis 54 isparallel to the central axis 56 of the support member 50, which issubstantially parallel to the central axis of the apparatus.

Having surgical blades 52 present on the apparatus during dilationtypically permits controlled cutting or lysis of any scar tissue presentin the patient's airway. The blades 52 should be clearly marked so thatusers can avoid inadvertently cutting themselves during placement of thesupport member 50 over the outer balloon. In one embodiment, the blades52 lay flat on the surface of the support member prior to use and priorto inflation of the outer balloon 12, and then when the outer balloonreaches a certain pressure upon inflation the blades 52 will typically“stand up” or otherwise protrude or expose their cutting edge atop theflexible support member 50. Once fully deployed, the exposed edge of theblade 52 typically only protrudes between about 0.2 to about 0.4 mm, andthe length of the blade is typically less than the length of the outerballoon 12. Typically there are a plurality of blades which are able towork together to embed into the stenosis or scar at a substantiallyuniform depth. For example, three blades could be permanently mounted onthe flexible support member, each of the blades being separated from theother blades so that each blade is free to move from a relatively flatposition to a cutting position on the flexible support member uponinflation of the outer balloon.

In practice, the airway balloon dilation procedure is typicallyperformed at the site of a stenosis in the airway of a patient (i.e. thelarynx, trachea or bronchi). Using the apparatus shown in FIG. 1, thesurgeon or clinician first inserts the apparatus 10 into the airway,then advances the apparatus within the airway until the outer balloon 12is across the stenosis. At this point, the surgeon or clinician inflatesthe outer balloon 12 to cause and allow the external surface 14 of theouter balloon 12 to expand upon and dilate the stenosis. To increasedilation pressures, the inner balloon 20 is then slowly inflated.Typically the inner balloon 20 is inflated after the inflation of theouter balloon 12. Under direct visualization, the balloons are typicallyinflated from between about 30 to about 120 seconds. The apparatus 10can also be threaded over a guidewire (not shown) which fits through thehollow core 18 and is positioned across the stenosis. Repeatinflation-deflation cycles can be done if airway narrowing remains afterthe initial attempt.

During balloon dilation, the size of the balloon is first selected bythe clinician, which depends upon the size of the stenosis in thepatient's airway. The balloon size is typically between about 10 mm toabout 40 mm in length. The outer balloon is positioned over the stenosisand then each balloon is individually dilated to the desired pressurewith a balloon pump, typically to between about 8 to about 20atmospheres. After these pressures are maintained for a predeterminedperiod of time, typically between about 60 to about 180 seconds, theballoons are deflated and the clinician determines if repeat inflationis necessary. Repeat inflation can be safely performed if there is noobvious trauma to the airway.

While the present invention has been illustrated by the description ofembodiments and examples thereof, it is not intended to restrict or inany way limit the scope of the appended claims to such detail.Additional advantages and modifications will be readily apparent tothose skilled in the art. Accordingly, departures may be made from suchdetails without departing from the scope or spirit of the invention.

1. An apparatus for performing an airway balloon dilation procedure atthe site of a stenosis in the airway of a patient, the apparatuscomprising: a central axis; a hollow core adapted to allow the patientto be ventilated therethrough; an inflatable outer balloon having anexternal surface; and at least one inflatable inner balloon, theapparatus being insertable into the airway of a patient for movement ofthe balloons therein between a deflated configuration and an inflatedconfiguration, the at least one inner balloon configured to inflateinside the outer balloon yet separately from the outer balloon.
 2. Theapparatus according to claim 1, wherein the inflatable outer balloon isdumbbell-shaped to hold the outer balloon in position over the stenosis.3. The apparatus according to claim 1, comprising a plurality of innerballoons.
 4. The apparatus according to claim 3, wherein there are threeinner balloons including a first inner balloon contained inside a secondinner balloon, the second inner balloon being contained inside a thirdinner balloon, all inner balloons being contained inside the outerballoon and being separately inflatable.
 5. The apparatus according toclaim 1, further comprising a flexible support member mounted along thecentral axis of the apparatus and on the external surface of the outerballoon, the flexible support member being substantially compliant withthe external surface of the outer balloon during movement therewith, andat least one microsurgical blade attached to the support member andadapted to form an effective cutting edge upon inflation of the outerballoon.
 6. The apparatus according to claim 5, wherein the apparatuscomprises a plurality of blades adapted to embed into the stenosis at asubstantially uniform depth.
 7. The apparatus according to claim 5,wherein the support member is made of a polyurethane material.
 8. Theapparatus according to claim 5, wherein the at least one blade is madeof stainless steel.
 9. The apparatus according to claim 5, wherein theat least one blade includes a blade axis, the at least one blade beingelongated and mounted on the support member with the blade axissubstantially parallel to the central axis of the apparatus.
 10. Amethod for performing an airway balloon dilation procedure at the siteof a stenosis in the airway of a patient, the method comprising: (1)inserting an apparatus into the airway, the apparatus including acentral axis, a hollow core adapted to allow the patient to beventilated therethrough, an inflatable outer balloon having an externalsurface, and at least one inflatable inner balloon, the apparatus beinginsertable into the airway of a patient for movement of the balloonstherein between a deflated configuration and an inflated configuration,the at least one inner balloon configured to inflate inside the outerballoon yet separately from the outer balloon; (2) advancing theapparatus within the airway until the outer balloon is positioned withinthe area of the stenosis; and (3) inflating the balloon to cause andallow the external surface of the balloon to expand upon and dilate thestenosis.
 11. The method according to claim 10, wherein the apparatusfurther comprises a flexible support member mounted along the centralaxis of the apparatus and on the external surface of the outer balloon,the flexible support member being substantially compliant with theexternal surface of the outer balloon during movement therewith, and atleast one microsurgical blade attached to the support member and adaptedto form an effective cutting edge upon inflation of the outer balloon,wherein the inflating step allows the at least one blade to form aneffective cutting edge upon inflation of the outer balloon.
 12. Themethod according to claim 11, wherein the apparatus comprises aplurality of blades adapted to embed into the stenosis at asubstantially uniform depth.
 13. The method according to claim 10,wherein the advancing step comprises the steps of: (i) inserting aguidewire into the airway of the patient; and (ii) tracking theguidewire with the apparatus to position the outer balloon across thestenosis.
 14. The method according to claim 10, further comprising thesteps of: (4) deflating the balloons after a predetermined amount oftime; (5) repeating steps (1) through (4) if airway narrowing remainsafter the initial attempt to dilate the stenosis fails; and (6) removingthe apparatus from the patient.
 15. An apparatus for performing anairway balloon dilation procedure at the site of a stenosis in theairway of a patient, the apparatus comprising: a central axis; a hollowcore adapted to allow.the patient to be ventilated therethrough; aninflatable, dumbbell-shaped outer balloon having an external surface; atleast one inflatable inner balloon; a flexible support member mountedalong the central axis of the apparatus and on the external surface ofthe outer balloon, the flexible support member being substantiallycompliant with the external surface of the outer balloon during movementtherewith; and at least one microsurgical blade attached to the supportmember and adapted to form an effective cutting edge upon inflation ofthe outer balloon, the apparatus being insertable into the airway of apatient for movement of the balloons therein between a deflatedconfiguration and an inflated configuration, the at least one innerballoon configured to inflate inside the outer balloon yet separatelyfrom the outer balloon, the dumbbell shape of the outer balloon adaptedto hold the outer balloon in position over the stenosis, and the atleast one blade adapted to form an effective cutting edge upon inflationof the outer balloon.
 16. The apparatus according to claim 15, whereinthe apparatus comprises a plurality of blades adapted to embed into thestenosis at a substantially uniform depth.
 17. The apparatus accordingto claim 15, wherein the support member is made, of a polyurethanematerial.
 18. The apparatus according to claim 15, wherein the at leastone blade is made of stainless steel.
 19. The apparatus according toclaim 15, wherein the at least one blade includes a blade axis, the atleast one blade being elongated and mounted on the support member withthe blade axis substantially parallel to the central axis of theapparatus.